Air flow regulating valve



ct- 19, 1948- w. A. MARSHALL, JR

AIR FLOW REGULATING VALVE :a sheets-sheet 1 Filed Feb. 12, 1945 T NT Oct 19, 1948- l w. A. MARSHALL, JR 2,451,526

, AIR FLOW REGULATING VALVE Filed Feb. 12, 1945 2 Sheets-Sheet 2 alim/'MS Patented oa. 19, 194eA AIR FLOW REGULATING VALVE William A. Marshall, Jr., Chicago, Ill., assignor to Stewart-Warner Corporation, Chicago, a corporation oflVirginia Ill.,

Application February 12, 1945. Serial No. '577,377'

The present invention lating valves and more particularly to an improved combustion air regulator for controlling the supply of combustion air to the combustion chamber of an internal combustion heater and particularly aircraft heaters. y i One of the primary-objects of the present invention isto provide a new and improved means for controlling the rate of supply of air for combustion to an internal combustionv heater.

Another object of .the present invention is to provide a new and improved combustion airflow regulator for internal combustion heaters wherein the rate of supply of air for combustion is regulated by means directly responsive to the pressure of the combustion air supplied to the heater.

Another object of the present invention is to provide a new and improved means for controlling the rate of supply of com-bustion air to an internal combustion heater wherein the rate of supply may be readily regulated. 4

A. further object of the present invention is to provide a new and improved air flow regulating valve, and especially one which can readily be applied to different types or size/s of apparatus, as for instance, different sizes or types of heaters.

Other objects and advantages of the present inrelates to air flow regu-l 2 Claims. (Cl. 137-452) vention will become apparent from the ensuing description in the course of which reference is had to the accompanying drawings, in which.

Figure 1 is a fragmentary longitudinal crosssectional view of a portion of an internal com-ous- Ation heater equipped with the combustion a-ir regulator of the present invention;

Figure 2 is a side-elevational view partly broken into section -to illustrate essential heater elements and the air regulating valve;

Figure 3 is an end elevational view of the apparatus illustrated in Figure 2, the view being taken along the line 3-3 of Figure 2;

Figure 4 is a plan view of the movable valve member, the view being taken along the line l--l of Figure 2; and

Figure 5 is an end elevational view of the valve member illustrated in Figure 4, the view being .taken along the line 5-5 of Figure 4.

In heaters, and particularlythose designed for use on aircraft, considerable diiilculty has been encountered in maintaining an adequate and yet not excessive supply of air for combustion in the 2 combustion chamber. This difficulty is particularly pronounced in heaters in which the milling` of the fuel and air takes place within the combustion chamber, i. e.,.in heaters in which the fuel is supplied directly into the combustion chamber. The air is supplied to the heater under pressure and generally through a ram-type inlet port with the result that the'pressure varies with .the speed of the aircraft. Thus, as the speed of the aircraft varies, the velocity and pressure of the air varies, with the result that the amount (weight) of air supplied to the heater varies.

These diflicul'ties are avoided in a simple and efficient manner through the use of my invention which comprises, in the main, a novel combustion air flow regulator or regulating valve capable of supplying a predetermined quantity of air to the combustion chamber under varying speeds. In the embodiment of Ithe invention about 'to be described, the valve is so constructed and arranged that a desired substantially constant amount of air is supplied -to the heater under varying speeds. For example, the amount of air thus supplied to -the heater may be about 3 pounds per minute.

Referring now .to the drawings, and especially Ito Figures 1 and 2, it may be noted that the heater has been indicated as a whole by reference character i0. It includes an outer metallic casing l2 within which is mounted a spiral type heat ex changer unit I4 at the upstream end (the left end as viewed in Fig. 1) of which is mounted a valve and combustion chamber assembly I6 constructed in accordance with the present invention. The assembly includes a combustion air flow regulating valve I8 including fixed and movable :members to be described in detail hereinafter and structure defining a combustion chamber 20 located centrally and at the upstream end of the heat exchanger.

The heat exchanger and its associated combustion chamber may be of various types and that illustrated in the drawings is one of a type with which the present invention may be utilized. Heat exchangers of this general character are discl-osed and claimed 'in the following copend'ing applications, all of which are assigned to the assignee of this invention: Application of William C. Parrish, Serial No. 490,162, filed June 9. 1943 and issued as Patent No. 2,432,929, dated December 16, 1947; application of William C. Parrish.

Serial No. 494,155, filed ananas July 10, 1943; and application of Arthur R. Collins, John H. Leslie II, and Charles T. Novak, Serial No. 553,-150, filed September 8, 1944.

The heat exchanger u nit I4 Is mounted substantially centrally of casing I2. Part of the air entering the upstream end of the casing is utilized as combustion air and flows to the combustion chamber in an amount determined by the air regulating valve I3 while part flows past the heat exchanger and is heated by the products of combustion. The products of combustion flow from the central combustion chamber' 20 through a spiral passageway 22 and are exhausted through an exhaust connection 24 located at the bottom of the heater and secured to the casing as by a flanged collar 26. I

The air to be heated flows lengthwise of the heat exchanger through a passageway 23 having a generally spiral cross-section. Suitable spacers are located in this passageway to provide the desired spacing `and to hold the heat exchanger in assembled relation. The construction of the heat exchanger of the spiral type is .more fully disclosed in the aforesaid Patent No. 2,432,929.

The combustion chamber includes a generally conical end member 32 suitably secured to the central part of the heat exchanger and supporting at its narrow upstream end a fuel supply fitting 33 detachably secured, as by screws, to a fuel supply and igniter tting34, preferably having generally the shape of a figure 8. The end member 32 is provided with a series of spaced apart apertures 35 through which the combustion air flows into the combustion chamber. Liquid hydrocarbon fuel is supplied under pressure and preferably in a substantially constant quantity to the combustion chamber through a fuel supply line 36 and a spray nozzle 33 detachably secured to the fitting 33. The fuel supply line 36 is secured to a hollow extension 40 of the tting as by a coupling 42. The nozzle 38 is secured to a central hollow portion 43 of the fitting in such manner that fuel is injected into the combustion chamber substantially centrally lengthwise of the same. A suitable fuel filter 44 is'secured to the inner end of the nozzle. An igniter 46 of the hot wire type is secured in good heat conducting manner to a downwardly extending portion 43 of the figure 8 shaped fitting 34. Electrical energy is supplied to the igniter through a conductor 50. The inner end of the 'igniteri projects into the combustion chamber a slight distance through an aperture 52 in the conical member 32. The igniteris enclosed within a closure tube 54 suitably secured as by welding or the like to the conical member 32 and to the extension 48 ofthe fitting 34. The foregoing fuel supply and igniter arrangement is more fully described and also claimed in the copending application of Lynn A. Williams, Jr., Serial No. 509,161, filed November 6, 1943, and assigned to the assignee of this application,

The fluid line 36 and conductor 50 are led to the fitting 33 through an airtight seal comprising a rubber washer 56 adapted to be compressed between a pair ofv washers 53 and 33.

- The compression is effected by rotation of an ex- 4 to be compressed by a flange secured to the upper end of the sleeve 32.

The combustion air nowing through cylindrical portion is directed to the combustion chamber by a short convergent tube 12 secured to thel inner `end of casing 66 and between the central portion of theheat exchanger and the inner end of tubular portion 32 of the combustion chamber.

The air valve I3 includes a stationary centrally apertured housing 14 having a smaller diameter upstream inlet end 13 and a larger diameter downstream end 13 and detachably secured in airtight `manner Vtofthe adjacent end of casing 66. The airtight connection can be effected by means of a anged collar 30 secured to the interior of casing 36 and supporting sealing gasket 32 between it and the end 13 of the stationary valve member 14. The latter is detachably secured to casing 66 b y means of a plurality of bolts 34 passing through bosses 36 in the stationary member and through brackets 36 secured to the exterior of the casing (Figs. 2 and 3).

Liquid fuel collecting at the bottom of casing 36 is'drained therefrom through a connection 90 leading from the bottom of the casing to the exhaust, as best illustrated in Figure 1.

The air valve I3 of the present invention may be constructedreadily and economically, may be readily attached to different sizes and types of units, and is actuated directly in response to the pressure of the air supply. It comprises a movable restriction valve member 92 so constructed and arranged that as the air pressure increases it gradually restricts the flow of the air to the comy bustion chamber by gradual closure of the central inlet port 94 at the small diameter end 'I6 of the fixed valve housing 14. The movement of the valve member 32 is restrained by a helical spring 66 which serves normally to maintain it in its maximum flow position. This position is determined by a stop bolt' 33 adapted to be secured in a predetermined adjusted position by a. stop nut |00. The stop bolt is secured at the upstream end of a yoke |02 including three spaced apart arms |04, the downstream ends of which are secured to bosses |06 formed on valve housing 14 by suitable means such as the screw bolts |01.

The movable valve member 92 is guided by a supporting and adjusting shaft |06' adjustably secured to an inwardly extending boss I 03 formed integral with the housing 14. The inner end of the shaft is threaded as indicated by reference character I |0, whereby the shaft may be locked in adjusted angularV position by means of the lock nuts ||2 at the outer extremity thereof and adapted to engage one side of the boss |03.

The movable valve member 92 is preferably made as an aluminum die casting. In order that it will not wear unduly in use, a sleeve II4 of suitable bearing material is mounted within the central opening. A stop'engaging button |I6 is mounted at the end of the valve for engagement with the stop bolt '33.

The movement restraining spring 96 is held within an annular recess I I3 cast in the valve and a cup-like' retainer |23 adjustably mounted upon a tubular externally threaded retainer support |22 pinned, as by a pin |24, for rotation with the shaft |06'. Rotational or angular movement of the retainer |20 is resisted by a; pin |26 carried in the bottom wall of the retainer and slidably extending into bore |23 in the boss |08 so that the retainer may be moved axially of the shaft to adjust the `pressure of 'the spring 96. The tubular support |22 bears against the opposite side of the boss |08 from lock nuts H2 whereby the shaft-is -held in adjusted position.

'The movement of the valve member relative tothe inlet port 84 regulates the flow of- `air to the combustion chamber. The maximum now is determined by the adjustment of the stop bolt I8, which determines the extreme limit of movement in port opening direction. The variation Y in effective port size in response to movement of short angular extent as compared to the gradually receding portions. The gradually receding portions may have an angle of about 6 degrees with respect to a plane normal to the axis while the sharply receding portions may include an angle of about 20 degrees. These portions form slot-like ports in the skirt of the movable valve member 92. y

In operation, the pressure of the air supply determines the position of the movable valve member and the effective port size. lThe spring 96 normally maintains the movable valve member in its outermost position whereat the stop bolt 98 bears against the stop-button IIB in the valve. As the air pressure increases the spring 96 is compressed and member 92 moves downstream to close more or less of the inlet opening between the housing 1| and the valve member 82 depending upon the pressure to maintain a substantially constant (or other desired) flow of air to the combustion chamber. e In initially adjusting the valve, the maximum flow adjustment is rst made by determining the outermost position of member 92 by the stop bolt 98. This is done with the spring 96 loaded to some desired value and at some lower air pressure.- Then the valve is subjected to a higher air pressure and the adjusting shaft 406' is rotated to load the spring to a desired extent whereat the now at the pressure (which may be the maxil'mum pressure) is at the desired value. The initial position should besuch that variations in 'lair pressure move. the movable valve member proportionately togthe pressure. Otherwise, as would be the case if the movable member were upstream beyond an effective flow control position, the control would not be proportional to the variations in pressure.

Different springsv could be used and, as already indicated, the effective port controllingsurfaces may be changed to give the desired control over positive but variable pressure forv diverting to the combustion chamber .of the heater a constant quantity of air froxn'the airflowing from said source, comprising: means forming a housing, an inlet to said housing, av generally cup-shaped valve member having a head against which the air entering said inlet impinges and having a cylindrical skirt adapted topro'ject into saidA inlet,

said skirt having ports therethrough, said valve being .telescopically movable with respect to said inlet to vary the effective area of said ports and Vthereby to control the flow vof air into said housing, saidvalve having an outer diameter slightly smaller than the diameter of said inlet so that when said valve is telescoped into said inlet there will be a narrow annular space between the outer cylindrical surface of said valve skirt and said inlet, a shaft axially disposed with respect to said inlet for supporting said valve member and guiding the movement thereof, a cup-shaped spring retainer-on said shaft having a skirt oppositely disposed with respect to theskirt on said valve and projecting thereinto, and a spring positioned about said shaft-.and reacting between the inner side of the head on said valve and the bottom of said retainer, said spring being adapted to yield upon variation in the pressure ofthe air on said valve member proportionately to the pressure, whereby the valve member is adjusted' to a position to maintain constant the amount of air flowing into said housing, and said retainer being quantity of air from the air flowing from said source, comprising: means forming a housing,

an inlet to said housing, a generally cup-shaped valve member having a head against which the vair entering said inlet impinges and having a the now of combustion air to the combustion chamber.

While a preferred embodiment of the present invention has been described in detail, it should be understood that the details thereof are not to be construed as limitative of the invention except in so far as set forth in the accompanying claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A combustion air regulator for an internal cylindrical skirt adapted to project into saidA inlet, said skirt having ports therethrough, said valve being telescopically movable with respect to said inlet to vary the effective area of said ports and thereby to control the flow of airinto said housing, said valve having an outer diameter slightly smaller than the diameter of saidinlet so that when said valveis telescoped into said inlet there will bea narrow annular space between the outer cylindrical surface of said valve. Y

skirt and said inlet, 'a shaft axially disposed with respect to said inlet for supporting said valve member and guiding the movement thereof, a cup-shaped spring retainer on said shaft having a skirt oppositely disposed with respect to the skirt on said valve vand projecting thereinto, a springpositioned about said shaft and reacting between the inner side of the head on said valve and the bottom of said retainer, said spring being I adapted to yield on variation in the pressure of the air on saidvalve member proportionately to the pressure, whereby the valve wmember is adjusted to a position Vto maintain constant the amount of air fiowinginto said housing, means for adjusting the tension of said spring including means on said shaft and rotatable therewith for forming a threaded connection between said shaft and said retainer to impart axial movement to said retainer relative to said shaft upon angular movement of said shaft, means including said threaded connection forming means for locking said shaft against angular movement,

combustion `heater which has a source of air of and means aligned with said shaft for limiting axial mbvement of said valve member outwardly Number 0f Bild inlet. 948,469 WILLIAM A. MARSHALL, Jl. 1,534,691 1,573,842 Y REFERENCES CITED 5 1,864,223 Y The following references are of record in the file of this patent. 22374389 UNITED STATES PATENTS l Number Name Date 1 412,189 Probert oct. 15, :aan mbe 674,889 187.755

Venn May 28, 1901 Name Date Moyle Feb. 8. 1910 Darby Apr. 21. 1925 Blades Feb. 9, 1926 ValJean June 21, 1932 Zoerb July 25, 1933 1 Mallory Aug. 7, 1934 Tramontini Apr. 24, 1945 FOREIGN PATENTS Country Date Great Britain July 13. 1922 

